Identification, quantification and analysis of observable anthropogenic debris along swiss river and lakes (IQASL)

IQASL is a project sponosored by the Swiss Federal Office for the environment to quantify shoreline trash along swiss lakes and rivers in the Rhone, Aare, Ticino and Linth/Limmat catchment areas. This is accomplished by conducting multiple small scale and discrete litter surveys throughout the river bassin. The majority of samples are taken from lakes.

What is a litter survey?

A litter survey is the identification and count of all objects found within a delimited area, in this study all surveys were bordered on one side by water. Each object is placed into one of 260 categories¹. The location, date, survey dimensions and the total number of objects in each category is noted.

Purpose of the surveys

The survey results help ALL stakeholders identify the items that make up the mass of trash found in the natural environment on the shores of Swiss lakes and rivers. The surveys answer the following questions:

  • What items are found?
  • How much is found ? (total weights and item counts)
  • How often are these items found?
  • Where do you find the most?

These are the most frequently asked questions and should be considered when determining any mitigation or reduction strategies.

The project is based on the following assumptions:

  • The more trash there is on the ground the more a person is likely to find
  • The survey results represent the minimum amount of trash at that site²
  • For each survey: finding one item does not effect the chance of finding another³

Purpose of this report

Summarize the results for the survey area and define the magnitude of those results with respect to other survey areas.

The survey results are presented as follows:

  • Total object count, total weight and weight of plastics
  • The most abundant objects from the survey area and all the other survey areas sorted by total object count
  • Pieces of trash per meter (pcs/m): the ratio of number of objects found to the length of the shoreline
  • Objects that were found in at least 50% of the surveys

Contents of this report

Scope: description of river basin

  • survey locations
  • lakes and rivers
  • municipalities and effected population

Survey dimensions, locations, aggregated totals

  • weights and measures: cumulative
  • weights and measures: cumulative by water feature
  • survey totals: pcs/m by date
  • material type: % of total

Trash removed: most abundant objects

  • the most common objects from the survey area
  • the most common objects from all the survey areas
  • pcs/m of most common objects for all water features in the survey area

Trash removed the most often

  • objects that are found in more than 50% of surveys
  • objects that are the most abundant
  • objects found in less than 50% of the surveys

Trash removed: utility

  • utility classification: % total of all objects found

Annex

  • effective data: report of missing records
  • survey location coordinates
  • population profile and results by municipality
  • itemized list of objects removed

More information

For more information about the project visit project home.

If you would like more information specific information about this survey area please contact:

  1. Swiss federal office for the environment - Municipal waste section
  2. analyst@hammerdirt.ch

¹ The EU guide on monitoring marine litter
² There is most likely more trash at the survey site, but certainly not less than what was recorded.
³ Independent observations : stats stackexchange

Results: Bielersee

Scope

The Aare source is the Aare Glaciers in the Bernese Alps of south-central Switzerland. The Aare is the longest river entirely within Switzerland with a length of 295 km and drainage area of 17,779 km2. Following the Aare Gorge, the river expands into the glacial Lake Brienz. The Aare is canalized at Interlaken before entering Lake Thun and exiting through the city of Thun.⁵ The river then flows northwest surrounding the old city center of Bern on three sides. Continuing west to Lake Wohlen Reservoir it turns north to Aarberg and is diverted west into Lake Biel by the Hagneck Canal, one of a series of major water corrections made in the 19th and 20th centuries connecting Neuchatel, Biel and Morat lakes through canalization. From the upper end of Lake Biel, at Nidau, the river exits through the Nidau-Büren Canal/Aare Canal.⁶

The Limmat and Reuss rivers⁷, two major tributaries converge into the Aare at the Limmatspitz between the cities of Brugg and Untersiggenthal in Canton Aargau.⁸ The Aare river ends in the north-western region of Koblenz, Switzerland where it joins the Rhine river which eventually terminates in the North Sea.

⁵ The Editors of Encyclopaedia Britannica. (1998, July 20). Aare River. Retrieved from Britannica.com: https://www.britannica.com/place/Aare-River
⁶ Standard Encyclopedia of Worlds Rivers and Lakes. (1965) R.K. Gresswell
⁷ The Limmat and Reuss are part of different survey areas
⁸ Pro Natura . (n.d.). Limmatspitz. Retrieved from Pro Natura : https://www.pronatura-ag.ch/de/Gebenstorf-limmatspitz

Survey locations, municipalities

For the period between 2020-01 and 2021-04, 4,618 objects were removed and identified in the course of 38 surveys. Those surveys were conducted at 9 different locations. There are 7 different municipalities represented in these results with a combined population of approximately 69,425.0

The municipalities in this report:

Biel/Bienne, Gals, Le Landeron, Ligerz, Lüscherz, Nidau, Vinelz

time to survey meters surveyed m² surveyed total weight plastic > 5mm weight plastic < 5mm weight staff help # samples labor hours pieces of trash
location
Bielersee_Vinelz_FankhauserS 39.67 238 536.0 3.099 1.864 0.000840 12 0 12 39 898
Camp des pêches 3.33 37 93.0 0.045 0.035 0.000000 1 0 1 3 53
Gals reserve 5.00 38 64.0 0.430 0.405 0.000001 2 0 2 5 48
Ligerz strand 5.67 15 49.0 0.295 0.294 0.000000 2 0 2 5 143
Lüscherz plage 9.91 236 517.0 1.570 0.232 0.000030 4 0 4 9 194
Lüscherz two 2.25 21 21.0 0.148 0.100 0.000000 1 0 1 2 8
Müllermatte 59.33 512 4291.0 5.588 3.348 0.001819 14 1 13 59 2964
Nidau strand 3.17 25 105.0 0.130 0.002 0.000236 1 0 1 3 63
Strandboden-Biel 7.15 93 420.0 2.250 0.440 0.000172 2 0 2 7 247

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Survey dimensions, location and aggregated totals.

Cumulative totals all data

The cumulative results from 38 samples, weights are in kilograms, time is in hours

index # samples pieces of trash meters surveyed m² surveyed total weight plastic > 5mm weight plastic < 5mm weight labor hours
summary total
Bielersee 38 4,618 1,215 6,096 13 6.72 0.0 132.0

Cumulative totals by water feature

# samples pieces of trash meters surveyed m² surveyed total weight plastic > 5mm weight plastic < 5mm weight labor hours
location
Bielersee_Vinelz_FankhauserS 12 898 238 536 3 1.864 0.000840 39
Camp des pêches 1 53 37 93 0 0.035 0.000000 3
Gals reserve 2 48 38 64 0 0.405 0.000001 5
Ligerz strand 2 143 15 49 0 0.294 0.000000 5
Lüscherz plage 4 194 236 517 1 0.232 0.000030 9
Lüscherz two 1 8 21 21 0 0.100 0.000000 2
Müllermatte 13 2,964 512 4,291 5 3.348 0.001819 59
Nidau strand 1 63 25 105 0 0.002 0.000236 3
Strandboden-Biel 2 247 93 420 2 0.440 0.000172 7

Survey totals pieces per meter, material type % of total

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The top ten most abundant items

Combined, the ten most abundant objects of the Bielersee represent 65% of all objects found in the survey area. Of the most abundant objects in the Bielersee, 6 are also among the most abundant when all the survey areas are combined.

  1. Expanded polystyrene
  2. Industrial sheeting
  3. Glass or ceramic drink bottles, pieces
  4. Food wrappers; candy, snack packaging
  5. Fragmented plastics
  6. Cigarette butts and filters

The most abundant objects: results by water feature

Some objects are found throughout the survey area and some of those objects are found in all survey areas. Knowing which objects are most abundant and what those values are helps idenitify sources or zones of accumulation.

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How often are these objects found?

Some objects are found often and in elevated quantities, others are found often and in small quantities and some times objects are found less often but in large quantities. Knowing the diffference can help find the sources.

Objects found in at least 50% of surveys AND among the most abundant objects found
Combined they had an average pieces per meter per survey of 2.68, a min of 0.05 and max of 10.0

1. Fragmented plastics
2. Industrial sheeting
3. Food wrappers; candy, snack packaging
4. Cigarette butts and filters
5. Glass or ceramic drink bottles, pieces
6. Expanded polystyrene
7. Industrial pellets (nurdles)
8. Insulation: includes spray foams and foam board
9. Cotton bud/swab sticks

Objects found in less than 50% of the surveys AND among the most abundant objects found
Combined they had an average pieces per meter per survey of 0.15, a min of 0.02 and max of 0.39

1. Styrofoam < 5mm

Objects found in at least 50% of the surveys AND NOT among the most abundant objects found
Combined they had an average pieces per meter per survey of 0.56, a min of 0.02 and max of 2.86

1. Foil wrappers, aluminum foil
2. Metal bottle caps, lids & pull tabs from cans
3. Other medical items (swabs, bandaging, adhesive plaster)
4. Tobacco; plastic packaging, containers
5. Plastic construction waste
6. Fireworks; rocket caps, exploded parts & packaging
7. Packaging plastic nonfood or unknown

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Utility: percent of total objects collected

Utility: The utility type is based on the utilisation of the object prior to it being discarded. Objects are placed into to one of the 260 categories. Those categories are grouped according to utilisation.

For example, a piece of plastic would be placed into the category 'Fragmented plastics', depending on its size. However, a piece of plastic that was once a bucket and we know this because we are familiar with either the brand or the product, is placed in a code for buckets⁸.

  • wastewater: items released from water treatment plants includes items likely toilet flushed
  • micro plastics (< 5mm): fragmented plastic items and pre-production plastic resins
  • infrastructure: items related to construction and maintenance of all infratructure items
  • food and drink: primarily single use plastic items related to consuming food and drinks outdoors
  • agriculture: primarily industrial sheeting includes
  • tobacco: primarily cigarette ends includes all smoking related material
  • recreation: includes fishing, hunting, boating and beach related objects, excludes food, drink and tobacco items
  • packaging non food and drink: packaging or wrapping material not identified as food, drink nor tobacco related
  • plastic fragments: foam and plastic fragments of indeterminate origin and use
  • personal items: accessories, hygiene and clothing related

⁸ See the annex for the complete list of objects identified, includes category and group classification

More information

Contact hammerdirt.ch for any questions about the content of this report. If you would like a report for your municipality contact the Swiss federal office for the environment: Municipal waste section.

Have a great day

This project was made possible by the Swiss federal office for the environment.
This document originates from https://github.com/hammerdirt-analyst/iqals all copyrights apply.
roger@hammerdirt.ch pushed the run button on 2021-05-22.

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Annex

  1. Effective data
  2. Populaion profile
  3. Survey location GPS
  4. Inventory of all objects removed
Effective data

The data is submitted in two parts. If a survey is missing either part we check the paper records and update when possible.

All the surveys found a home in the dimensional data
These dimensional records have been dropped, there is no matching survey data:

('luscherz-plage', '2021-01-26').

Population profile

The samples come from a variety of locations. Certain locations were sampled at monthly intervals others through out the year.

33.57
19
Auto-assigning NUTS sampler...
Initializing NUTS using jitter+adapt_diag...
Multiprocess sampling (3 chains in 4 jobs)
NUTS: [beta, alpha]
Sampling 3 chains, 0 divergences: 100%|██████████| 6000/6000 [00:01<00:00, 4123.44draws/s]
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-47-0c99edd6223e> in <module>
     10 
     11     trace_g = pm.sample(draws=n_draws, chains=n_chains, tune=n_draws)
---> 12     ppc = pm.sample_posterior_predictive(trace, samples=1000, model=model, size=1)

NameError: name 'trace' is not defined

The median pieces per meter per survey of the most abundant objects by municipality

Annex

Survey locations:

Annex

Inventory of all items